This invention relates generally to centrifugal force operated hydraulic governors and more particularly to a hydraulic governor adapted to be mounted adjacent the periphery of an automatic transmission output shaft and adapted to provide a two-stage transmittal of governor pressure in response to changes in output shaft speed.
Briefly, this invention comprises a housing member rotatably supported for rotation with the output shaft of an automatic transmission, a first-stage piston valve fluidly connected to a source of line pressure in the transmission and operative under the influence of centrifugal force to transmit pressurized fluid to shift actuating members of the transmission at a level proportional to the square of the output shaft, and a second piston valve member also slidably received in the housing and resiliently biased against the influence of centrifugal force created by rotation of the output shaft and commonly fluidly connected to the source of line pressure with the first piston valve member and operative to supply a pressure signal proportional to the square of the speed of the output shaft to a portion of the first piston valve member to modify the pressure output thereof. Each of the piston valve members also includes means for effecting outboard venting of contaminants under the influence of centrifugal force.
One of the primary objects of the invention is to provide a hydraulic governor adapted to be mounted on the output shaft assembly of an automatic transmission without requiring an aperture be provided through the output shaft to provide interconnection between components effecting two-stage operation.
Another object of the invention is to provide a hydraulic governor of the type described which may be conveniently mounted on pre-existing components of the transmission output shaft assembly.
A further object of the invention is to provide a hydraulic governor of the type described which has a single body member containing a pair of valve members adapted to operate in response to changes in the rotational speed of the output shaft to the transmission to modify a line pressure and produce pressure related to the speed of rotation of the output shaft.
Still another object of the invention is to provide a hydraulic governor of the type described which utilizes passages formed in the housing for fluidly interconnecting the two valve members.
Yet another object of the invention is to provide a hydraulic governor of the type described that is radially removable from the output shaft.
A further object of the invention is to provide a hydraulic governor of the type described which is economical in construction and effective in operation.
Other objects and advantages of the invention will be apparent to those skilled in the art of hydraulic governors upon reading the accompanying description and claims.